Generally you need to spark people's curiosity and let them ask you questions about bitcoin, rather than try preaching it. That's from my experience more effective. Like you could start "yeah, I'm into Bitcoin, I spent waaay tooo much time reading the details and trying to understand how it works and what it does. We don't have to get into that if you don't want to, because I could talk long hours about it." [friendly smile]
Usually people will reply with something negative, but with a bit of curiosity, like
  • "I don't think it has a chance to catch up" - you could continue that it's in El Salvador and you can pay for coffee in Starbucks,
  • "I heard it just wastes so much energy" - you could carefuly start hinting that energy can be used for good things and that US Dollar is backed by US Army eating a lot of energy too,
  • if person is hearing it for the first time "and so what is it?" - try avoiding any technobabble, just say oh it's this easy way to send money between people everywhere around the world. Like I can literally send money to someone in Ethiopia in couple seconds. And it's legal in most of the countries.
With some people it takes time to plant the seed. Don't mention Bitcoin at all, but talk about inflation first, how it's hurting people. Talk about the US dollar, how it's used as a tool to steal value from other countries. Talk about sending money abroad and that there is so much extra fees...